This invention relates to hybrid semiconductor devices. By "hybrid" is meant two or more separate components which are electrically and mechanically interconnected to form a semiconductor device. The invention has particular utility in the fabrication of hybrid semiconductor rectifiers, particularly two phase bridge rectifiers.
One well known semiconductor bridge rectifier circuit comprises four semiconductor diodes connected as shown in FIG. 1. In use, an A.C. voltage is applied across the terminals A and B, and a D.C. current flows through a load L always in the direction from terminal C to terminal D.
An example of a known bridge rectifier device 20 is shown in FIG. 2. The device 20 comprises two stacks of diodes; one stack comprising two diode semiconductor die or chips 10 and 12 (see, also FIG. 1) and the other stack comprising two diode semiconductor chips 14 and 16. The two chips 10 and 12 are connected together by means of a terminal D which is sandwiched between the two chips and which extends laterally outwardly from the two-chip stack (e.g., perpendicular to the plane of the drawing). Similarly, the two chips 14 and 16 are connected together and sandwich therebetween an outwardly extending terminal C.
A terminal A electrically and mechanically interconnects the two diode stacks and is electrically connected to the anode of the diode chip 10 and to the cathode of the chip 14. Similarly, a terminal B electrically and mechanically interconnects the anode of the chip 12 and the cathode of the chip 16.
With the various diodes interconnected as shown in FIG. 2, the assembled device comprises a bridge rectifier which can be utilized as shown in FIG. 1.
A feature of the device shown in FIG. 2 is that the two terminals C and D extend laterally outwardly from the two diode stacks and lie in a common plane. The terminal A extends laterally beyond the top end of one of the diode stacks and then downwardly and laterally in the plane of the terminals C and D. Similarly, the terminal B extends laterally beyond the bottom end of the other diode stack and then upwardly and laterally in the common plane. An advantage of disposing all the terminals in a common plane is that it facilitates mounting of the rectifier device on a printed circuit board. For example, the rectifier (encapsulated in a plastic envelope, not illustrated) can be mounted on a printed circuit board with the in-plane terminals A, B, C and D pressed against a surface of the circuit board. The terminals are then soldered to printed circuit paths on the circuit board which extend beneath the rectifier terminals.
Heretofore, the rectifier devices shown in FIG. 2 have been assembled more or less manually, e.g., by successively disposing the various components of the device, i.e., the individual terminals A, B, C and D, and the individual diode chips 10, 12, 14 and 16, into contoured cavities in a jig, and then simultaneously soldering together the components.
The present invention is concerned with automated fabrication of hybrid devices. The invention is described in connection with the fabrication of devices of the type shown in FIG. 2, but the utility of the invention is not limited to such device fabrication.